.alpha.-Unsaturated amine derivatives or salts thereof having potent inhibitory actions against harmful pests and the like have been employed as insecticides. It has been found that such amines can be admixed with other insecticides and/or fungicides to form advantageously valuable agrochemical compositions (EPC Patent Application Laid Open No. 302,389; corresponding to Japanese Patent Application Laid Open No. 171/1990).
Further, these compounds are of low toxicity to human beings, domestic animals, fish and natural enemies of pests. For practical use, these compounds are admixed with, for example, a carrier and/or bulking agent to form a conventional solid formulation or preparation such as a dust, granule, wettable powder, wettable granule, seed treating agent, microgranule F, etc.
However, the .alpha.-unsaturated amine derivatives and their salts are considerably unstable in the solid formulation wherein said amines are admixed with a carrier and/or bulking agent (e.g. mineral powder). As these compounds are stored at an ambient temperature (30.degree. C.) for long time, they are gradually decomposed. As a result, this causes the formulation to suffer a decrease in the content of the active ingredient. Moreover, in the case where the amine is admixed with one or more species of other agrochemical active substances in order to achieve high activity in a wide range and simultaneous control for saving labor, the decomposition and deterioration of such amines and their salts in the mixed formulation is frequently more serious than that in the single formulation.
The .alpha.-unsaturated amine derivatives and their salts have an advantageous property for the environment because of their relatively rapid photodegradation. However, there is a possibility that the preparation could decrease high pesticidal activity by the decomposition of said amines due to sunlight in the case of sprinkling on paddy fields, or uplands.
In general, various techniques for stabilizing agrochemicals have been developed (EPC Patent Application Laid Open No. 280,289; corresponding to Japanese Patent Application Laid Open No. 4/1989 and Japanese Patent Application Laid Open No. 4209/1987). Nevertheless, such prior art techniques cannot solve the problems as described above.
It is still desired to develop a stable agrochemical formulation comprising the .alpha.-unsaturated amine derivative or its salt.